Myriophyllum rubricaule sp. nov., a M. aquaticum look-alike only known in cultivation

  • Johan L.C.H. Van Valkenburg National Reference Centre for plant health, NVWA, Geertjesweg 15, 6706 EA Wageningen/Postbus 9102, 6700 HC Wageningen, The Netherlands
  • Leni (H.) Duistermaat Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden/Postbus 9517, 2300 RA Leiden, The Netherlands
  • Edu Boer National Reference Centre for plant health, NVWA, Geertjesweg 15, 6706 EA Wageningen/Postbus 9102, 6700 HC Wageningen, The Netherlands
  • Tom M. Raaymakers National Reference Centre for plant health, NVWA, Geertjesweg 15, 6706 EA Wageningen/Postbus 9102, 6700 HC Wageningen, The Netherlands
Keywords: Myriophyllum, water-milfoil, EU regulation no. 1143/2014, invasive plant, horticulture


A confusingly labeled water-milfoil of obscure status, known only in cultivation, is here formally described as a new species, Myriophyllum rubricaule Valk. & Duist. sp. nov. This species has fully replaced M. aquaticum in the horticultural trade in Europe since the addition of M. aquaticum to the list of invasive alien species of Union concern (EU regulation no. 1143/2014) in 2016. This manuscript provides a morphological description of M. rubricaule sp. nov., and its distinction from M. aquaticum is further supported by molecular data (chloroplast and nuclear loci).


Beringen R. 2020. Myriophyllum trade name ‘brasiliensis’. In: FLORON Verspreidingsatlas Vaatplanten. Available from [accessed 21 Sep. 2021].

Brunel S. 2009. Pathway analysis: aquatic plants imported in 10 EPPO countries. EPPO Bulletin 39: 201–213.

Crow G.E. & Ritter N.P. 1999. Myriophyllum mattogrossense (Haloragaceae), a rare lowland watermilfoil new to Bolivia. Rhodora 101: 28–39.

Edgar R.C. 2004. MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research 32: 1792–1797.

EPPO-Q-bank. 2022. Myriophyllum sp. trade name “brasiliensis” (Z00259). Available from [accessed 21 Sep. 2021].

Ghahramanzadeh R., Esselink G., Kodde L.P., Duistermaat H., van Valkenburg J.L.C.H., Marashi S.H., Smulders M.J.M. & van de Wiel C.C.M. 2013. Efficient distinction of invasive aquatic plant species from non-invasive related species using DNA barcoding. Molecular Ecology Resources 13: 21–31.

Hulme P.E., Brundu G., Carboni M., Dehnen-Schmutz K., Dullinger S., Early R., Essl F., González-Moreno P., Groom Q.J., Kueffer C., Kühn I., Maurel N., Novoa A., Pergl J., Pyšek P., Seebens H., Tanner R., Touza J.M., van Kleunen M. & Verbrugge L.N.H. 2018. Integrating invasive species policies across ornamental horticulture supply chains to prevent plant invasions. Journal of Applied Ecology 55: 92–98.

Jukes T.H. & Cantor C.R. 1969. Evolution of protein molecules. In: Munro H.N. (ed.) Mammalian Protein Metabolism: 21–132. Academic Press, New York.

Kress W.J. & Erickson D.L. 2007. A two-locus global DNA barcode for land plants: the coding rbcl gene complements the non-coding trnH-psbA spacer region. PLoS ONE 2 (6): e508.

Kress W.J., Erickson D.L., Jones F.A., Swenson N.G., Perez R., Sanjur O. & Bermingham E. 2009. Plant DNA barcodes and a community phylogeny of a tropical forest dynamics plot in Panama. Proceedings of the National Academy of Sciences USA 106: 18621–18626.

Kumar S., Stecher G., Li M., Knyaz C. & Tamura K. 2018. MEGA X: Molecular Evolutionary Genetics Analysis across computing platforms. Molecular Biology and Evolution 35: 1547–1549.

Lü T.-F., Li X., Wang S.-N., Han L., Hao F., Fu C.-L., Zhang P. & Liu X. 2017. Allohexaploid speciation of the two closely related species Myriophyllum spicatum and M. sibiricum (Haloragaceae). Aquatic Botany 142: 105–111.

Meijden R. van der & Caspers N. 1971. Haloragaceae. In: van Steenis C.G.G.J. (ed.). Flora Malesiana. Ser. I. Vol. 7: 23–263. Wolters-Noordhoff Publishing, Groningen.

Moody M.L. & Les D.H. 2010. Systematics of the aquatic angiosperm genus Myriophyllum (Haloragaceae). Systematic Botany 35: 121–139.

Orchard A.E. 1980. Myriophyllum (Haloragaceae) in Australasia. I. New Zealand: A revision of the genus and a synopsis of the family. Brunonia 2: 247–287.

Orchard A.E. 1981. A revision of South American Myriophyllum ( Haloragaceae), and its repercussions on some Australian and North American species. Brunonia 4: 27–65.

Orchard A.E. 1986. Myriophyllum (Haloragaceae) in Australasia. II. The Australian species. Brunonia 8: 173–291.

Orchard A.E. & Kasselmann C. 1992. Notes on Myriophyllum mattogrossense (Haloragaceae). Nordic Journal of Botany 12: 81–84.

Pot R., van Valkenburg J.L.C.H., Duistermaat H. & Boer E. 2021. Invasive aquatic plants in Europe. Identification key. Available from [accessed 21 Sep. 2021].

Q-bank Invasive Plants. 2019–2021. Myriophyllum sp. trade name “brasiliensis”. Available from [accessed 21 Sep. 2021].

Sang T., Crawford D.J. & Stuessy T.F. 1997. Chloroplast DNA phylogeny, reticulate evolution, and biogeography of Paeonia (Paeoniaceae). American Journal of Botany 84: 1120–1136.

Tamura K. 1992. Estimation of the number of nucleotide substitutions when there are strong transition-transversion and G+C-content biases. Molecular Biology and Evolution 9: 678–687.

Tate J.A. 2002. Systematics and evolution of Tarasa (Malvaceae): an enigmatic Andean polyploid genus. PhD thesis. The University of Texas (Austin), USA.

Thiers B. continuously updated. Index Herbariorum: A Global Directory of Public Herbaria and Associated Staff. New York Botanical Garden’s Virtual Herbarium. Available from [accessed 25 May 2022].

Thum R.A., Mercer A.T. & Wcisel D.J. 2012. Loopholes in the regulation of invasive species: genetic identifications identify mislabeling of prohibited aquarium plants. Biological Invasions 14: 929–937.

Van Valkenburg J.L.C.H. & Boer E. 2015. Cabomba and Myriophyllum in trade, What’s in a name? In: Newman J. (ed.) Abstracts 47th Robson meeting, Reading, England: 16–17, Waterland management, United Kingdom.

Van Valkenburg J., Duistermaat L., Westenberg M. & van de Vossenberg B. 2015. Myriophyllum in trade in Western Europe, what species are we really talking about? In: Aquatic Plants 2015, 14th International Symposium on Aquatic Plants: 57. The Centre for Ecology & Hydrology, Edinburgh, United Kingdom.

Verbrugge L.N.H., Leuven R.S.E.W., van Valkenburg J.L.C.H. & van den Born R.J.G. 2014. Evaluating stakeholder awareness and involvement in risk prevention of aquatic invasive plant species by a national code of conduct. Aquatic Invasions 9: 369–381.

Wang D., Yu D. & Li Z.-Y. 2002. Myriophyllum exasperatum (Haloragaceae), a new species from China. Annales Botanici Fennici 39: 267–271.

Wang D. & Yu D. 2007. A new subspecies of Myriophyllum oguraense (Haloragaceae) from China. Annales Botanici Fennici 44: 227–230.

White T.J., Bruns T., Lee S. & Taylor J. 1990. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis M.A., Gelfand D.H., Snisnky J.J. & White T.J. (eds) PCR Protocols: A Guide to Methods and Applications: 315–332. Academic Press, San Diego.

Yu D., Wang D. & Li Z.-Y. 2002. Taxonomic revision of the genus Myriophyllum (Haloragaceae) in China. Rhodora 104: 396–421.

How to Cite
Van Valkenburg, J. L., Duistermaat, L. (H.), Boer, E., & Raaymakers, T. M. (2022). Myriophyllum rubricaule sp. nov., a M. aquaticum look-alike only known in cultivation. European Journal of Taxonomy, 828(1), 1-15.
Research article